rekordbox link no longer working after update

after updating to the latest version of rekordbox, the link function no longer works . linking via djm2000nxs and 3x cdj2000. latest firmware installed on mixer and cdj's. i ensured to change firewall settings for new rekordbox but no success. i can see my 3 cdj's on the rekordbox screen but when i try to drag and drop a track i get this error message

error 8302 cdj 2000 c611

all other functions of rekordbox software appears to be functioning, link function did work properly in previous 4.x.x versions of rekordbox. 

thank you